Everyday. I can’t stress the importance of brushing your hair extensions everyday, before you clip them in, and at least once during wear throughout the day. This keeps them from tangling with your own hair, from looking piece-y and from matting up. But do not just with any brush… the Cashmere Hair brush is the only one recommended for use with Cashmere Hair Clip In Extensions. This is because it is specially designed to detangle with minimal stress on the hair. So not only will your hair extensions look refreshed but they will last longer.